Abstract Library

#4566 Predictive value of high-risk histopathological- and molecular criteria for lymph node metastasis in appendiceal neuroendocrine tumours

Introduction: Appendiceal neuroendocrine tumours (aNET) are rare neoplasms for which consensus is needed for follow-up and additional treatment. To unravel the factors behind aNET which showed lymph node metastasis (LNM) in additional right hemicolectomy (RH), we evaluated high-risk histopathological parameters in aNETs and studied molecular parameters.

Conference:

Presenting Author: Bremer B

Authors: Bremer B, Kyriskozoglou V, El Moumni M, Heideman D, Walenkamp-Hageman A,

Keywords: Appendix NET, High-risk histopathological criteria, Serotonin, Driver mutation, Right Hemicolectomy,

#4166 Characterising the tumor microenvironment of multifocal small intestinal NETs

Introduction: Small intestinal neuroendocrine tumors (SI-NETs) are thought to arise from enterochromaffin cells of the gut, often with multiple synchronous primary tumors. Recently, we showed that synchronous primary tumors from the same SI-NET patient display distinct somatic mutational profiles, suggesting that these tumors originate independently, despite few clear driver mutations. Thus, new mechanistic insights into multifocal SI-NETs are urgently needed.

Conference:

Presenting Author:

Authors: Mäkinen N, Lee I, Dohlman A, Gao T, Zhang Z,

Keywords: small intestinal NET, tumor microenvironment, tumor microbiome,

#2982 Comprehensive Molecular Analysis Identifies Driver Mutations in Metastases of Sporadic Well-Differentiated Neuroendocrine Tumours of the Small Intestine

Introduction: Small intestinal neuroendocrine tumours (SI-NETs) represent a heterogenous group of tumours. The molecular mechanisms which contribute to progression of SI-NETs are poorly elucidated. They are considered to be molecularly distinct from neuroendocrine carcinomas (NECs), which share oncogenic pathways with adenocarcinomas.

Conference: 17th Annual ENETSConcerence (2020)

Presenting Author: Samsom K

Authors: Samsom K, van Veenendaal L, Roepman P, Kodach L, Steeghs N,

Keywords: whole genome sequencing, neuroendocrine tumour, small intestine, genetics,

#2234 High Rate of Copy-Number Alterations in Gastrointestinal and Pancreatic Neuroendocrine Tumors with Unidentified Driver Mutations

Introduction: The driving genetic alteration leading to neuroendocrine tumor (NET) development has been reported for primary tumors of pancreatic origin, but not for metastases. Moreover, even for primary tumor a significant “dark matter” remains to be explored.

Conference: 15th Annual ENETSConcerence (2018)

Presenting Author: Tirosh A

Authors: Tirosh A, Killian J, Zhu Y, Neychev V, Meltzer P,

Keywords: GEP-NET, Driver mutation, Copy-number, Metastases,

#2126 Histone Replacement in Cancer: Dissecting the Role of H3.3 Chaperones in Pancreatic Tumorigenesis

Introduction: Cancer driver mutations affecting the histone H3.3 chromatin remodellers ATRX and DAXX were recently discovered in 43% of sporadic pancreatic neuroendocrine tumours (PNET). Progressive age-dependent replacement of canonical H3.1/2 with H3.3 is crucial for maintaining genome integrity through expression of repressive markers at heterochromatic sites, where loading is mediated by ATRX and DAXX. Loss of H3.3 chaperones in PNET is associated with activation of ALT, a telomere maintenance mechanism, eventually leading to chromosome instability. It has been suggested that ATRX/DAXX expression is necessary for repressing ALT, but mechanistic details of this interaction are not fully understood.

Conference: 15th Annual ENETSConcerence (2018)

Presenting Author: Sposito T

Authors: Sposito T, C Nguyen Tu M, Thirlwell C, Salomoni P,

Keywords: PNET, mouse model, epigenetic,